Roller squeegee device with fluid pressure increasing means

ABSTRACT

A squeegee device with a roller squeegee for applying a fluid on a material particularly for screen printing includes a guide wall or guide wall member positioned adjacent the periphery of the roller squeegee and extends to the region where the fluid is applied to the material to be worked. The guide wall has a concave face facing the roller squeegee with a gap formed therebetween. The gap is filled with the liquid or viscous compound so that the hydrodynamic pressure of the liquid in the gap is increased. The guide wall may have a cross section of a rounded upper edge and two concave outer surfaces tapering to a pointed lower edge, with one of the concave faces following the curve of the squeegee, the pointed lower edge pointing downwardly and projecting into the region under the roller squeegee. The guide wall may also be formed as part of the limitation wall of a squeegee box, into which the squeegee roller is pivotally mounted.

Unite Kudlich States atent PRESSURE INCREASING MEANS 462,160 2/ 1969Switzerland 101/ 120 [75] Inventor: Hans Kudlich, Obemdorf-Ebbs,1,569,439 5/1969 France 101/ 120 Austria [73] Assignee: Peter Zimmer,Kufstein, Austria Primary Pulfrey Assistant Exarruner-R. E. Suter [22]F1led: July 20, 9 Attorney, Agent, or Firm-Wenderoth, Lind & Ponack 21Appl. No.: 164,332

. [57] ABSTRACT U-S. A squeegee device a roller queegee for [51] Int. ClB411 15/42 a fl id on a i l i larly for screen printing [58] Field ofSearch 101/1 19, 120, 124, includes a guide wall or guide Wall memberpositioned 101/114, 116, 123, 121, 122; 415/90; adjacent the peripheryof the roller squeegee and ex- 417/300; 418/154 tends to the regionwhere the fluid is applied to the material to be worked. The guide wallhas a concave [56] References C'ted face facing the roller squeegee witha gap formed UNITED STATES PATENTS therebetween. The gap is filled withthe liquid or vis- 2,664,050 12/1953 Abresch 418/154 @0113 Compound 80that the hydrodynamic Pressure of 2,753,794 7/1956 Groak 101 120 x h q iin h gap i increased. The guide wall may 2,782,843 2/1957 Rodenacker...415/90 X have a cross section of a rounded upper edge and two 3,303,7912/1967 Doble 418/154 on ave outer surfaces tapering to a pointed lower3,669,561 6 1972 Mott 417/300x edge, with one f the concave faces f ll ithe 3,198,109 8/1965 Dwyer et a1. 101/119 x curve of the squeegee thepointed lower edge pomp 2,419,695 4/1947 Shuttleworth et a1 101/116 UX gdownwardly and p j g into the region under 2,180,135 11/1939Bartho1omew..... 101/119 th Th n l b 3,487,775 1 1970 Chaney et a1101/114 6 er Squeegee e wa may a so 6 3,098,437 7/1963 Tyma, Jr. eta1... 101/350 formed as Part of the hmltatlon wall of a Squeegee2,206,570 7/1940 Johnston 101/116 X box, into which the Squeegee rolleris Pivotally 2,792,780 5/1957 Jacob 101/119 mounted- 3,352,234 -11/1967Londahl et a1 101/114 3,596,595 8/1971 Zimmer et a1. 101/120 10 Claims13 Drawing Figures (I) 9 ii 20 5] Apr. 30, 19 74 FOREIGN PATENTS ORAPPLICATIONS vA'immara-somu $8071.30? sum 1 HF INVENTOR HANS KUDLICHATTORNEYS PRTENIEB APR 30 5974 SHEET 2 0F 7 INVENTOR HANS KUDLICH BYflinM v M ATTORNEYS PAYENIEBAPR 30 m4 SHEET 3 0F 7 INVENTOR HANS KUDLICH B2 /7 flaw/M ATTOVRNEYS sgsomoz PATTEBAPR 30 m4 SHEEI [IF 7 INVENTORHANS KUDLICH BY #14 r ATTOR NEYS PATENTEBAPR 30 1974 SHEET 5 OF 7INVENTOR HANS KUDLICH WYW ATTORN EYS SHEEI 8 0? Y INVENTOR HANSKUDLICIiI ATTORNEY5 y/wiz ROLLER SQUEEGEE DEVICE WITH FLUID PRESSUREINCREASING MEANS BACKGROUND OF THE INVENTION This invention relates to asqueegee device having a rotating roller squeegee for applying a liquid,in particular a highly viscious compound, onto the surface of a materialto be worked, particularly for screen printing.

With known squeegee devices it is not possible to apply large quantitiesof liquid onto the material to be printed. This can result, e.g., inscreen printing, in unsatisfactory premeation or the liquid into thetextile.

SUMMARY OF THE INVENTION It is an object of the invention to increasethe quantity of liquid applied to the material without prematurepenetration. This object is achieved by providing a guide wall or guidewall member adjacent the periphery of the roller squeegee to provide agap therebetween. A concave face of the guide wall faces the rollersqueegee, and the guide wall extends into the region where the liquid isapplied to the material. Thus, the liquid is prevented from contactingthe material in an uncontrolled manner. The pressure of the liquid inthe gap is increased to ensure better penetration of the goods by theliquid. Also, the gap stabilizes the flow of the liquid. This isadvantageous, particularly in the case of printing machines with aprinting velocity of more than 100 m/min.

The bottom edge of the guide wall projects into the region under theroller squeegee filled with the liquid.

In accordance with the present invention the wedgeshaped space servingfor the hydrodynamic increase in pressure between roller squeegee andmaterial to be worked or the rotary screen is enlarged by the gap formedbetween the guide wall and the roller squeegee so that a higher pressurecan develop in the liquid. This results in a larger quantity of theliquid being applied to the material to be worked by means of thesqueegee device according to the invention. Also, due to the enlargedgap any detrimental turbulences are prevented in squeegee devices infast operating machines (e.g., fast operating rotary screen printingmachines).

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention arehereinafter described in detail with reference to the accompanyingdrawings, without, however, being limited thereto.

FIG. 1 is a vertical section of and FIG. 2 is a section according toline II-ll of FIG. 1 ofa printing device in a rotary screen printingmachine;

FIG. 3 is a vertical section in an enlarged scale of the squeegee deviceshown in FIGS. 1 and 2;

FIG. 4 is a top view of and FIG. 5 is a section according to line V-V ofFIG. 4 of a modified embodiment of the lateral end region of thesqueegee device;

FIG. 6 is a top view of and FIG. 7 is a section according to lineVII-VII of FIG. 6 of a modified embodiment of the lateral end region ofthe squeegee device;

FIGS. 8l3 are vertical sections of further embodiments of the squeegeedevice according to the invention.

DETAILED DESCRIPTION OF THE INVENTION The embodiment according to FIGS.1 to 3 is a squeegee device for a rotary screen printing machine. In arotary screen 1 whose end pieces 2 are rotatably mounted in screenbearings 3 which are connected to the machine frame 4, there is mounteda roller squeegee 5. The roller squeegee 5 consists of magnetizablematerial and is attracted by a magnet body attached to the pressuresupport 6. The magnet body may consist of a series of verticallyarranged magnet cores 7, enclosed byspools 8. The material to be printed9 is moved between the rotary screen I and the pressure support 6 bymeans of a printing blanket 10. While the material to be printed 9 andthe printing blanket 10 move in the direction of arrow 11, the rotaryscreen 1 rotates in the direction of arrow 12 and the roller squeegee 5rolls along the inside wall of the screen in the direction of arrow 13.The dye is fed in a manner known per se by a dye tube 14 provided withoutlet appertures to a dye supply 15 lying between squeegee 5 and screen1 upstream of the direction of rotation thereof. Upon rolling along theinside wall of the screen the roller squeegee 5 presses the dye from thedye supply I5 through the holes of the screen onto the sheet of materialto be printed 9.

According to the invention a guide wall 16 is provided in the dye supply15, this guide wall extending substantially over the whole width ofroller 5. In crosssection the guide wall has a rounded upper edge andtwo concave outer surfaces tapering to a pointed lower edge. One concavesurface of the guide wall extends a small distance from and generallycoaxially to the cylindrical surface of the roller. Thus a relativelynarrow gap 18 is formed between the guide wall and the roller. The guidewall is connected to the dye tube 14 by arms 17 such that on rotation ofdye tube 14 the width of the gap varies.

As can best be seen from FIG. 3 the trailing or lower edge of the guidewall extends well into the printing area, i.e., the region 19 where dyeis to penetrate through the screen 1 into the material 9.

If in such device, screen and material move in the directions of thearrows 13, 12 and 11, respectively, dye is conveyed by adhesion to thesurface of roller 5 through the gap 18 between the roller 5 and theguide wall 16 toward the printing region where it is squeezed throughthe screen into the material. This requires considerable pressure whichmay build up gradually from the upper or entrance end of the gap 18,since from this entrance the dye is positively guided and prevented fromflowing either into the lower part of the dye supply or through thescreen before reaching the printing region 19. Some but considerablyless pressure rise is obtained in the gap 20 between guide wall 16 andscreen 1.

On the contrary, in known devices, any liquid pressure build up occursonly approximately over region 19, the length of which is only about onefourth of the length of gap 18. Accordingly, the maximum pressureobtainable with guide wall 16 may be about four times higher thanwithout the guide wall, and because of the increase of pressure, theamount of liquid applied to the material increases.

The amount of pressure rise in gap 18 can be controlled by turning thedye tube 14 changing thereby the width and shape of gaps l8 and 20.Noses 21 which are provided on the guide wall assure a minimum distancebetween the guide wall and the roller.

In the embodiment shown in FIG. 2 the gap 18 between roller squeegee andguide wall 16 is open at both longitudinal ends, so that liquid may passtherethrough, resulting in a certain pressure decrease. This can beeffectively prevented by seals attached to the ends of the rollersqueegee, as shown in FIGS. 4 and 5 and FIGS. 6 and 7. According toFIGS. 4 and 5 a resilient cylindrical ring 23 preferably madeof a porousmaterial, is mounted on ashaft 22 of the roller squeegee 5. The outerdiameter of ring 23 is greater than the outer diameter of roller 5, suchthat in its uncompressed condition, ring 23 closes the end of gap 18 bybearing against the transverse end plane 24 of guide wall 16, therebypreventing escape of liquid. In the contact area between ring 23 androtary screen 1 the ring 23 is compressed as can be seen from FIG. 5.The ring 23 thus also seals rotary screen 1. The modification accordingto FIGS. 6 and 7 shows a ring having frustro-conical sealing lips 25having the same function as ring 23. Sealing lips 25 are arranged on theshaft 22 of the roller squeegee 5. The inner lip 25 bears against endplanes 24 of guide wall 16, thus forming a sliding seal. In order toprevent any damage to lips 25 likely to be caused by the sharp edge 26between roller squeegee 5 and shaft 22, a ring 27 is arranged in frontof sealing lips 25. Ring 27 consists of an elastomeric material ofrelatively high Shore hardness.

FIGS. 8 to are further embodiments of squeegee devices according to theinvention, also for use in rotary screen printing machines.

According to FIG. 8 the roller squeegee 5 is arranged in a squeegee boxhaving four generally vertical walls, two of which are shown as 28 and31 and which extend parallel to the axis of roller 5, and the other twowalls (not shown) are perpendicular to walls 28 and 31. A guide wall 64is attached to wall 28, and its concave surface forms a gap 18 withroller 5 through which dye from the dye supply is fed by the dye tube 14to the region 19, thus effecting a gradual pressure increase in the dyeduring its passage through gap 18. The guide wall 64 is sealed offtowards the rotary screen 1 by a flexible sealing member 29, secured tothe guide wall 16 by means of a wedge fastener 30. Thus there remainsonly one gap 18, contrary to the arrangement of FIGS. 1 to 3. The bottompart of wall 31 ofthe squeegee box has a low friction seal 32 providinga support for the roller squeegee 5 and thus sealing it. The squeegeebox is fastened by clamps 33 to the dye tube 14. If the squeegee box ismoved upwardly with respect to roller squeegee 5 in the direction ofarrow 34, the gap 18 narrows and the increase of pressure changes in thegap. If the lower end of guide wall 64 approaches the periphery of theroller very closely, flow of liquid is throttled, and pressure andquantity of flow will decrease. On the other hand, excessive lowering ofthe box will result in a wide gap in which'the trailing action of theroller surface will not extend over the whole width thereof, such thatnear the guide wall 64 stagnation of flow or even back flow may occur,thereby also decreasing the rate of flow. Thus, a'maximum flow isobtained with a gap of certain width which depends on the form of thegap, the rotational speed, viscosity of liquid.

In the embodiment according to FIG. 9 the roller squeegee 5 is arrangedin a squeegee box. Guide wall 65 differs from the embodiment of FIG. 8in that it replaces wall 28 and that it extends over almost half thecircumference of the roller squeegee 5. The pressure increasing gap 18is therefore longer than in the aforementioned embodiments and thusresults in a higher pressure and greater flow of liquid.

The embodiment according to FIG. 10 is similar to that of FIG. 9, exceptthat a cylinder 35 is mounted inside the squeegee box above rollersqueegee 5 and offset horizontally with respect thereto. Cylinder 35 isprovided on the surface thereof with a coating 36 having a series ofresilient strips 38 extending parallel to the axis of cylinder 35 andinclined with respect to the radii of the cylinder passing through thebases of the strips. In the squeegee box the dye supply 15 has the level37. A chamber 39 formed between adjacent strips 38 is filled with dyeunder level 37. If the roller squeegee 5 moves in the direction of arrow13 and the cylinder 35 moves in the direction of arrow 40, the dye istransported to the entrance 41 of gap 18. When strips 38 reach thispoint, they are bent flat by nose 42, and the liquid within chamber 39is forced downwardly into gap 18, thereby increasing the pressure.Within gap 18 between roller 5 and guide wall 6, a further increase ofpressure is effected because of the rotation of roller squeegee 5 andthe ensuring carriage of the dye in the gap 18. In this embodiment avery high pressure is produced.

Very high pressure can alsobe obtained by the arrangement according toFIGS. 11 and 12. In a squeegee box 43 a second roller 44 is arrangedabove the normal roller squeegee 5. the twp rollers rotate in oppositedirections indicated by arrows 60 and 13. The surfaces of the innerwalls of the box follow closely the outer surfaces of the rollers 5 and44 on one side thereof. On the other sides are formed gaps 46 and 18through which die is conveyed downwardly from supply 15 fed from a dyetube (not shown). While flowing through gap 46 the dye builds up apressure as described above. Thus, when reaching the gap transition area47 the dye has already a considerable pressure which is furtherincreased when passing through gap 18. Noses 21 extending through thegaps in the direction of flow assure proper spacing of the rollers. Area47 provides compensation of the forces acting on roller 5. By thepressure increase in gap 18 at the lower portion of roller 5, higherspecific pressures act on the bottom portion of the roller than on theupper portion thereof. These forces consequently tend to push roller 5upwardly. This is;compensated, at least partially, by the provision ofarea 47 which acts to some degree as a retaining surface. q I

The sealing of the dye under pressure in area 59 is effected in thecircumferential direction of roller squeegee 5 on the one hand by theroller squeegee 5 contacting the rotary screen and on the other hand bya sealing lip 53, e.g., of polytetrafluorethylen. Sealing lip 53 extendsparallel to the axis of the roller squeegee 5 and is attached tosqueegee box 43 and insures that the dye is forced through screen 1 overthe distance 19. There can also be provided a plurality of sealing lips.

By changing the speed of rotation of cylinder 44, which does not touchthe rotary screen 1, the pressure increase in the dye can be influencedand accordingly adapted as conditions may necessitate. For an intensivefeeding of dye or for a strong penetration of the material to be printed(e.g., piled goods) the speed of rotation of the cylinder 44 must behigher than that of the roller squeegee 5. It would be useful in thisconnection as a variant to the embodiment shown. to make gap 46 narrowerthan gap 18. The roller squeegee 5, touching the rotary screen 1 iseither simply moved by the rotary screen or is driven in such way thatthe circumferential speed of the roller squeegee 5 is constantly equalto the circumferential speed of the rotary screeen 1, so that there willpractically be no wear between roller squeegee 5 and rotary screen 1.The wear of rotary screen 1 by sealing lip 53 is insignificant, the moreso if lip 53 is made of a material having a low coefficient of frictionwith regard to the screen material (preferably nickel). This isparticularly the case with polytetrafluorethylen.

An example for the drive of roller squeegee 5 and cylinder 44 can beseen in FIG. 12. Roller squeegee 5 has a shaft 22 projecting therefrombearing a gear wheel 48. Gear wheel 48 meshes with a gear wheel 49 whichalso drives a gear wheel 50 secured to the end of the rotary screen 1.The gear ratios of gear wheels 48 and 50 are designed, in an understoodmanner, to bear a relationship with the diameters of roller squeegee 5and rotary screen 1 such that the roller squeegee 5 and rotary screen 1have the same circumferential speed when gear wheel 49 is driven bydrive means 45. Roller 44 is driven by a rotation device 52 via a shaft51 permanently secured to the end of cylinder 44. The driving device 52can be a continuous transmission gear receiving its driving motion fromthe repeat drive 45. Driving device 52 may also be an engine whose speedof rotation is variable to a desired gear ratio to the main drive 45.

The purpose of the electromagnets 8 in printing table 6 is to press theroller squeegee 5 toward the wall of the screen and to prevent upwarddisplacement of the squeegee box 43 and thus also a lifting of sealinglip 53 from the inside wall of the screen. For this purpose the rollersqueegee 5 consists at least partially of magnetizable (ferromagnetic)material.

In the embodiment according to FIG. 13 the roller 5' is not in directcontact with the rotary screen 1. Rather, a lower dye chamber 61 isprovided between roller 5' and screen 1. It is the object of thisarrangement to prevent any wear of the rotary screen 1, which may have athickness of only some tenths of a millimeter according to moderngalvanoplastic methods of production, even if the roller 5 is driven ata higher circumferential speed than the rotary screen 1 for the purposeof a more intensive dye application. The printing blanket with the sheetmaterial 9 thereonmoves in the direction of arrow 11. The rotory screen1 rotates in the direction of arrow 12. In the interior of the rotaryscreen 1 there is a squeegee box 43, whose dye supply 15 is fed with dyefrom the dye tube 14.

According to FlG. 13 there is only one roller 5' in the squeegee box 43of the squeegee device, such roller rotating in the direction of arrow13. Roller 5 can be driven by a rotating device arranged outside therotary screen 1, so that the speed of rotation is adjustable. Dependingon the speed of rotation of roller 5', a predetermined pressure increaseof the dye flowing through gap 18' is created. The pressure of theliquid in the area 61 beneath the roller 5 is determinative of theamount of dye forced through the holes of the rotary screen 1 in thearea of zone 19 between the sealing lips 53, 54.

lt is not important whether the roller 5 rotates in the same directionor in the opposite direction as screen 1. It is a feature of thisembodiment that the roller 5' does not contact the rotary screen 1, thisbeing attained by the position of roller 5' in the squeegee box 43. Thesealing of the squeegee box 43 with rotary screen 1 is effected bysealing lips 53, 54, which are pressed onto the wall of the screen bymeans of support means 62 of magnetizable material positioned at thebottom If the squeegee box. The support means are attacted by the effectof the elctromagnets 8, whereby the squeegee box 43 and the sealing lips53, 54 are drawn toward the rotary screen 1. The dye which passessealing lip 54 is removed by squeegees or doctor blades 55 and 56. Bymeans of plane 57 linked to the squeegeed 55, the dye removed from theinterior of screen 1 is supplied to the supply 15 of the squeegee box43. The dye removed from the outside of the screen by the squeegee 56 isremoved through a channel 58.

The squeegee device according to the invention in general as well as tothe shown embodiments in particular are not limited to the applicationin rotary screens of rotary screen printing machines. Such squeegeedevices can also be used with flat screens or even for applying a liquidor viscous compound without the use of screens.

1 claim:

1. A squeegee device for applying liquid, in particular highly viscousliquid, onto the surface of a material,

said device comprising a perforated screen; a rotatable roller squeegeemounted for the application of said liquid onto said material throughsaid screen; and a stationary guide wall member having a concavesurface, said guide wall member being mounted such that said concavesurface is spaced from and extends substantially parallel to thecylindrical peripheral surface of said roller squeegee, and over theentire length thereof, thereby forming a gap between said rollersqueegee and said guide wall member, there being a plane extendingthrough the axis of said roller squeegee and the line formed by thepoints on said roller squeegee positioned most closely to said screen,said guide wall member being mounted on that side of said plane whereina point on the cylindrical peripheral surface of said roller squeegeeand screen approach each other during movement thereof, the lower edgeof said guide wall member being positioned between said roller squeegeeand said screen; whereby said liquid is conveyed, on rotation of saidrollr squeegee, through said gap towards the surface of the material andthe pressure of said liquid in said gap is increased.

2. A squeegee device as claimed in claim 1, wherein said guide wallmember is displaceably mounted for varying the width of said gap.

3. A squeegee device as claimed in claim 1, wherein the longitudinallengths of said roller squeegee and said guide wall member aresubstantially equal, said guide wall member having plane surfacestransverse to the longitudinal length thereof at each of its oppositeends; and further comprising a resilient cylindrical ring attached toeach opposite end of said roller squeegee and coaxial thereto, the outerdiameters of said rings being greater than the diameter of said rollersqueegee, said rings contacting said transverse plane surfaces of saidguide wall member, thereby closing the opposite ends of said gap, andforming a sliding seal with said plane surfaces upon rotation of saidroller squeegee.

4. A squeegee device as claimed in claim 1, wherein the longitudinallengths of said roller squeegee and said guide wall member aresubstantially equal, said guide wall member having plane surfacestransverse to the longitudinal length thereof at each of its oppositeends; and further comprising a sealing ring attached to each oppositeend of said roller squeegee and coaxial thereto, a frustroconicalsealing lip extending from the outer surface of each of said ringstowards the respective one of said transverse plane surfaces thuslaterally closing said gap and forming a sliding seal with said planesurfaces upon rotation of said roller squeegee.

5. A squeegee device as claimed in claim 1, wherein the cross section ofsaid guide wall member has a rounded upper edge and two concave outersurfaces tapering to a pointed lower edge.

6. A squeegee device as claimed in claim 1, further comprising asqueegee box having four substantially vertical walls, said rollersqueegee being mounted in said squeegee box, one of said vertical wallsforming said guide wall member.

7. A squeegee device as claimed in claim 6, further comprising a secondroller mounted in said squeegee box above said roller squeegee, saidsecond roller being rotated by a variable speed drive.

8. A squeegee devices as claimed in claim 7, wherein said second rolleris rotated in a direction opposite to that of said roller squeegee.

9. A squeegee device as claimed in claim 7, wherein a second of saidvertical walls of said squeegee box forms a second guide wall memberdesigned to define a second gap between said second roller and saidsecond guide wall member,'liquid being conveyed through said second gapto the entrance of said gap between said second roller squeegee and saidguide wall member on rotation of said second roller.

10. A squeegee device as claimed in claim 9, wherein said second gapis'narrower than said gap between said roller squeegee and said guidewall member.

1. A squeegee device for applying liquid, in particular highly viscousliquid, onto the surface of a material, said device comprising aperforated screen; a rotatable roller squeegee mounted for theapplication of said liquid onto said material through said screen; and astationary guide wall member having a concave surface, said guide wallmember being mounted such that said concave surface is spaced from andextends substantially parallel to the cylindrical peripheral surface ofsaid roller squeegee, and over the entire length thereof, therebyforming a gap between said roller squeegee and said guide wall member,there being a plane extending through the axis of said roller squeegeeand the line formed by the points on said roller squeegee positionedmost closely to said screen, said guide wall member being mounted onthat side of said plane wherein a point on the cylindrical peripheralsurface of said roller squeegee and screen approach each other duringmovement thereof, the lower edge of said guide wall member beingpositioned between said roller squeegee and said screen; whereby saidliquid is conveyed, on rotation of said rollr squeegee, through said gaptowards the surface of the material and the pressure of said liquid insaid gap is increased.
 2. A squeegee device as claimed in claim 1,wherein said guide wall member is displaceably mounted for varying thewidth of said gap.
 3. A squeegee device as claimed in claim 1, whereinthe longitudinal lengths of said roller squeegee and said guide wallmember are substantially equal, said guide wall member having planesurfaces transverse to the longitudinal length thereof at each of itsopposite ends; and further comprising a resilient cylindrical ringattached to each opposite end of said roller squeegee and coaxialthereto, the outer diameters of said rings being greater than thediameter of said roller squeegee, said rings contacting said transverseplane surfaces of said guide wall member, thereby closing the oppositeends of said gap, and forming a sliding seal with said plane surfacesupon rotation of said roller squeegee.
 4. A squeegee device as claimedin claim 1, wherein the longitudinal lengths of said roller squeegee andsaid guide wall member are substantially equal, said guide wall memberhaving plane surfaces transverse to the longitudinal length thereof ateach of its opposite ends; and further comprising a sealing ringattached to each opposite end of said roller squeegee and coaxialthereto, a frustroconical sealing lip extending from the outer surfaceof each of said rings towards the respective one of said transverseplane surfaces thus laterally closing said gap and forming a slidingseal with said plane surfaces upon rotation of said roller squeegee. 5.A squeegee device as claimed in claim 1, wherein the cross section ofsaid guide wall member has a rounded upper edge and two concave outersurfaces tapering to a pointed lower edge.
 6. A squeegee device asclaimed in claim 1, further Comprising a squeegee box having foursubstantially vertical walls, said roller squeegee being mounted in saidsqueegee box, one of said vertical walls forming said guide wall member.7. A squeegee device as claimed in claim 6, further comprising a secondroller mounted in said squeegee box above said roller squeegee, saidsecond roller being rotated by a variable speed drive.
 8. A squeegeedevices as claimed in claim 7, wherein said second roller is rotated ina direction opposite to that of said roller squeegee.
 9. A squeegeedevice as claimed in claim 7, wherein a second of said vertical walls ofsaid squeegee box forms a second guide wall member designed to define asecond gap between said second roller and said second guide wall member,liquid being conveyed through said second gap to the entrance of saidgap between said second roller squeegee and said guide wall member onrotation of said second roller.
 10. A squeegee device as claimed inclaim 9, wherein said second gap is narrower than said gap between saidroller squeegee and said guide wall member.